An FDA-approved clinical trial is being conducted to test whether a non-invasive technology safely and effectively reduces pain from bone metastases. This outpatient procedure destroys the pain-causing nerves in the bone surface surrounding the tumor to relieve pain.
This non-invasive technology is called Magnetic Resonance guided Focused Ultrasound (MRgFUS), and is being used on an ExAblate system.
MRI-guided FUS: history, present & future
Ferenc Jolesz, M.D.
Director, National Center for Image Guided Therapy
Professor of Radiology, Harvard Medical School
The application of acoustic energy for tumor treatment is not a new idea. More than a half century ago, focused ultrasound (FUS) was already considered viable as a ―surgical‖ technique for treating deeply embedded soft tissue tumors non-invasively. Despite this early recognition of its potential, FUS has not been widely accepted as a real alternative to invasive surgery. The reason is not the limitation of focused ultrasound technology but the inadequacy of image-guidance and the control of energy deposition. We strongly believe that the integration of FUS with Magnetic Resonance Imaging (MRI) represents a major step towards a non-invasive image-guided therapy substitute that can replace most of the existing tumor surgery methods. MRI guided Focused Ultrasound Surgery (MRgFUS) that has been developed during the last decade provides accurate targeting of focused sound waves that can be directed to destroy tumor tissue within MRI detected tumor margins. MRI not only provides tumor localization with high sensitivity but also monitors temperature distribution in /real time/, effectively generating ―temperature maps‖ of the targeted surgical field/ /during treatment. In turn, FUS delivers thermal energy at safe, therapeutically effective doses /without/ damaging collateral normal tissue. The integration of MRI and FUS creates an image-guided therapy delivery system with which /real time/, image-controlled, non-invasive soft tissue coagulation is feasible; and from which a wide range of clinical applications may ultimately benefit.
Although MRgFUS technology is still in its infancy, this revolutionary disruptive imaging technology has already been established as a viable, non-invasive treatment for uterine fibroids, breast carcinomas, certain brain malignancies, and for palliative treatment of bone tumors. With additional research, we will no doubt develop MRgFUS applications for CNS and vascular diseases, targeted drug delivery, gene therapy, and more. The integration of MRI and Focused Ultrasound Surgery (FUS) has resulted in/ real time/, image-controlled, closed loop-feedback based, non-invasive therapy delivery systems. Moreover, MRI has the ability to control tissue heating and the deposition of thermal dose. This feature significantly improves the safety and efficacy of FUS in the treatment of tumors. The major advantage of MRI-guidance over other imaging modalities is its ability to achieve accurate targeting while avoiding thermal injury of normal tissues. Over the next decade, MRgFUS will almost certainly replace several invasive open surgeries and will likely supplant minimally invasive approaches as the preferred treatment approach.